linux-kernel - Re: [PATCH RFC v2 0/7] drm/display: dp: add new DPCD access functions

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87a59ywda3.fsf@intel.com>
Date: Thu, 06 Mar 2025 14:32:04 +0200
From: Jani Nikula <jani.nikula@...ux.intel.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, Lyude Paul
 <lyude@...hat.com>, Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
 Maxime Ripard <mripard@...nel.org>, Thomas Zimmermann
 <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, Simona Vetter
 <simona@...ll.ch>, Rob Clark <robdclark@...il.com>, Abhinav Kumar
 <quic_abhinavk@...cinc.com>, Sean Paul <sean@...rly.run>, Marijn Suijten
 <marijn.suijten@...ainline.org>
Cc: dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
 linux-arm-msm@...r.kernel.org, freedreno@...ts.freedesktop.org
Subject: Re: [PATCH RFC v2 0/7] drm/display: dp: add new DPCD access functions

On Sat, 01 Mar 2025, Dmitry Baryshkov <dmitry.baryshkov@...aro.org> wrote:
> Existing DPCD access functions return an error code or the number of
> bytes being read / write in case of partial access. However a lot of
> drivers either (incorrectly) ignore partial access or mishandle error
> codes. In other cases this results in a boilerplate code which compares
> returned value with the size.
>
> As suggested by Jani implement new set of DPCD access helpers, which
> ignore partial access, always return 0 or an error code. Reimplement
> existing helpers using the new functions to ensure backwards
> compatibility.

I think that description is for earlier versions of the series, it's the
other way round now.

Regardless, glanced through the series quickly, I like it, this is

Acked-by: Jani Nikula <jani.nikula@...el.com>


>
> This series targets only the DRM helpers code. If the approach is found
> to be acceptable, each of the drivers should be converted on its own.
>
> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
> ---
> Changes in v2:
> - Reimplemented new helpers using old ones (Lyude)
> - Reworked the drm_dp_dpcd_read_link_status() patch (Lyude)
> - Dropped the dp-aux-dev patch (Jani)
> - Link to v1: https://lore.kernel.org/r/20250117-drm-rework-dpcd-access-v1-0-7fc020e04dbc@linaro.org
>
> ---
> Dmitry Baryshkov (7):
>       drm/display: dp: implement new access helpers
>       drm/display: dp: change drm_dp_dpcd_read_link_status() return value
>       drm/display: dp: use new DCPD access helpers
>       drm/display: dp-aux-dev: use new DCPD access helpers
>       drm/display: dp-cec: use new DCPD access helpers
>       drm/display: dp-mst-topology: use new DCPD access helpers
>       drm/display: dp-tunnel: use new DCPD access helpers
>
>  drivers/gpu/drm/amd/amdgpu/atombios_dp.c           |   8 +-
>  .../gpu/drm/bridge/cadence/cdns-mhdp8546-core.c    |   2 +-
>  drivers/gpu/drm/display/drm_dp_aux_dev.c           |  12 +-
>  drivers/gpu/drm/display/drm_dp_cec.c               |  37 ++-
>  drivers/gpu/drm/display/drm_dp_helper.c            | 307 +++++++++------------
>  drivers/gpu/drm/display/drm_dp_mst_topology.c      | 105 ++++---
>  drivers/gpu/drm/display/drm_dp_tunnel.c            |  20 +-
>  drivers/gpu/drm/hisilicon/hibmc/dp/dp_link.c       |   4 +-
>  drivers/gpu/drm/msm/dp/dp_ctrl.c                   |  24 +-
>  drivers/gpu/drm/msm/dp/dp_link.c                   |  18 +-
>  drivers/gpu/drm/radeon/atombios_dp.c               |   8 +-
>  include/drm/display/drm_dp_helper.h                |  92 +++++-
>  12 files changed, 322 insertions(+), 315 deletions(-)
> ---
> base-commit: c0eb65494e59d9834af7cbad983629e9017b25a1
> change-id: 20241231-drm-rework-dpcd-access-b0fc2e47d613
>
> Best regards,

-- 
Jani Nikula, Intel